[Puke]

yep. often it is because of an inteligence operation, but sometimes they just do it when they get really unhappy (or random event). their empire name will usually be named after their planet or system, but they will share all of the racial qualities with their parent race.

(they are usually really easy to get to surrender, as they only start with one world, and they start with it mid-late in the game)

you should have a first contact notice from them too..